The present disclosure relates to a vehicle seat, and particularly relates to a vehicle seat including an expandable bag body at shoulder support portions configured to support a corresponding one of the shoulders of a seated passenger, each shoulder support portion being provided at a seat back configured to support the seated passenger from a back side.
Among vehicle seats, there is a vehicle seat including, in a seat back, an expandable/contractible bag body such as an air cell for the purpose of, e.g., adjustment of a seating posture of a seated passenger. According to the seat with such a configuration, a seating surface shape is changed by expansion/contraction of the bag body so that the seating posture can be adjusted. Examples of the seat including the expandable/contractible bag body include a seat described in Japanese Patent No. 2664599.
In the seat described in Japanese Patent No. 2664599, each of an upper bag portion and a lower bag portion in a seat back includes an air mat as a bag body, and a support panel at a front position of the air mat. By expansion of the air mat, the support panel tilts forward to push the back of a seated passenger forward, and in this manner, a seating posture of the seated passenger is adjusted. Particularly in the upper bag portion, when the support panel tilts forward by expansion of the air mat, the shoulders of the back of the seated passenger are pushed forward.
Note that the examples of the seat including the expandable/contractible bag body include seats other than the vehicle seat, and as an example, there is a relaxing chair described in Japanese Patent Publication JP 2001-112565. In a bag body provided in this relaxing chair, any of liquid, fluid, a mixture of liquid and grains, and solid containing flexibility is housed as a medium. When a user is seated on the relaxing seat and leans on a back portion of the relaxing seat, the above-described bag body comes into close contact with the back of the seated user. As a result, a favorable feeling of fitting can be provided to the seated user of the relaxing chair.
In order to properly adjust the seating posture of the seated passenger and properly provide the favorable feeling of fitting, the bag body provided in the seat needs to properly expand/contract at an arrangement position of the bag body. For proper expansion/contraction, a direction in expansion of the bag body needs to be stabilized. In order to stabilize such a direction, a fixed state of the bag body needs to be stabilized. Particularly in proper adjustment of the degree of pushing (pressing force) of the bag body pushing the vicinity of a corresponding one of the shoulders of the passenger seated on the seat, the fixed state of the bag body needs to be further stabilized. On the other hand, Japanese Patent No. 2664599 and Japanese Patent Publication JP 2001-112565 describe the arrangement position of the bag body, but do not mention the way to fix the bag body. That is, a specific configuration for stabilizing the fixed state of the bag body is not clearly described in Japanese Patent No. 2664599 and Japanese Patent Publication JP 2001-112565.
In addition to the above-described demand for stabilizing the fixed state of the bag body pushing the vicinity of a corresponding one of the shoulders of the seated passenger, it has been demanded that such a bag body is fixed at a proper position to properly push a corresponding one of the shoulders of the seated passenger. Further, in the configuration in which the shoulders of the seated passenger are pushed through the plate-shaped member disposed at the front position of the bag body as described in Japanese Patent No. 2664599, the plate-shaped member needs to be supported so that the plate-shaped member can fulfill functions thereof.